Increasing HIV testing rates among young, African American or Black men who have sex with men (YBMSM) is critical to reducing the disproportionate disease burden in the African American/Black community. Rates of new HIV infections increased 48% between 2006 and 2009 among YBMSM; a recent study reported a nearly 6% annual HIV incidence among YBMSM. A significant portion of YBMSM has not tested in the prior year and YBMSM are 7 times more likely to be unaware of their HIV infection, as compared to other young MSM. The stigma associated with accessing fixed site HIV testing prevents many YBMSM from testing. In addition, alcohol and other drug (AOD) use represent a significant barrier to HIV prevention, including testing, among YBMSM, reflecting complex social structures, enhancing the impact of stigma and discrimination. We propose a study to design and test a brief intervention to increase uptake of consistent HIV self-testing among YBMSM using a novel and culturally-relevant buddy system approach. In our model, peer educators train pairs of YBMSM (or buddies) to initiate self-testing and support each other in consistent self-testing (every 3 months) and sexual and AOD use risk reduction. The self-test is a promising new method that reduces several barriers to testing for YBMSM, such as HIV testing stigma, homophobia, mistrust of medical care providers/system, limited access, and confidentiality/privacy concerns. The intervention, which is brief, focused and tailored, has three primary components. First, buddies will receive a 25-minute self-testing skills-building, motivation- enhancing and peer support-focused session, rapid HIV testing and free self-test kits at our fixed site or on our mobile testing unit. Second, additional self-tests will be deliverd (or accessed) as needed, using the delivery method of their choice. Third, booster messages, based on personalized testing plans developed during the initial session, will be delivered using preferred type of communication technology (e.g., texts, e-mail, calls). A peer educator will deliver the intervention and on-demand technical support will be available from the study team using the full range of communication technology. As part of the study, we propose to conduct 30 in- depth interviews to identify barriers to, facilitators of, perceptions of and preferences fo regular HIV self- testing, describe how AOD use and sexual behavior influence HIV self-testing behaviors, and assess participant perspectives on the proposed buddy intervention. Next, based on the formative research, we will use intervention mapping to adapt couples testing, integrating enhanced motivational interviewing techniques to create a brief, peer educator-delivered, face-to-face intervention. Finally, we will use web- and app-based approaches to recruit 376 HIV-negative, BMSM aged 18 to 24 who will be randomized as pairs to either the intervention arm (skills training; free test kits on demand; tailored booster messages) or the control arm (generic health screening information; free test kits on demand) and followed for 12 months to estimate the intervention's efficacy in increasing regular self-reported HIV self-testing